Simultaneous Equation

From the first equation you can see that $\displaystyle x=14+3y$
So plug $\displaystyle 14+3y$ into the second equation in the place of $\displaystyle x$ then solve that for $\displaystyle y$. Once you have the value of $\displaystyle y$ plug that back into either equation to get the value of $\displaystyle x$.
Let us know if you have trouble with this.

Wouldn't be useful here. Elimination method is only useful when the fact of adding or substracting together both equations gets rid of an unknown (like $\displaystyle -2x$ in the first one and $\displaystyle 2x$ in the second). Here you wouldn't get anything useful [I never ever use the elimination method, oddly enough I prefer using substitution in all problems ...] but if you are asked to do the Elimination method ...